SciMac’s Drain Valve consists of a PTFE plunger with a center bore that allows the contents of the vessel to drain directly through the center of the plunger permitting complete mixing of the contents of the flask. When closed, the tip of the Teflon plug seals flush into the lower opening of the flask avoiding any crevasse that could collect sample material, and also permits complete drainage of the vessel. Additionally, the plunger has 2 PTFE covered O-rings. The complete Valve consists of a Glass body, PTFE stem and Delrin control cap.